1. Field of the Invention
The present invention relates to an audio plug and, more particularly, an audio plug with a contact shaft for an electrical connection of an electrical conductor, and a metal tube provided on the contact shaft.
2. Description of Prior Arts
A great number of audio plugs of the most varied constructions are known. These numerous constructional forms are disclosed in many publications.
U.S. Pat. No. 5,290,179 discloses an audio plug comprising primarily a tubular shaft served as an external contact, a bushing having a greater diameter than the shaft and covering on the shaft, and a gripping sleeve receiving the bushing and the shaft. The bushing which carries an external thread adjacent to the aforementioned shaft is slid onto the shaft. The gripping sleeve with a central bore hole for a passage of a cable. One end of the gripping sleeve has an internal thread by which the gripping sleeve can be screwed onto the thread of the bushing and covers the aforementioned shaft.
However, such previously known constructions are proper to be used in a larger electronic device. When a small audio plug is needed, it is difficult to design precise threads on the bushing and the gripping sleeve. Moreover, the gripping sleeve, to the extent that it is constructed in one piece and is made of harder material, extends over the cable in a cantilevering manner. Since there is no soft cooperation at the end of the gripping sleeve to accommodate the cable, the cable can only exert a limited distortion. If the cable extends or twists, one end thereof connecting with the gripping sleeve will be broken in two parts. Then a desirable transmission between the audio plug and the electronic device will be broken.
Therefore, the present invention is directed to solving these various problems by providing an improved cable connector.